In the past, heat pump systems have been utilized to collect heat from either the ambient atmosphere or sunlight. Other sources of heat energy have also been tapped, such as water reservoirs and underground heat sources.
The invention utilizes a plate which may be inclined at an angle to the sun such that it will serve as a solar collector. It may consist of a plate of any type to which tubes have been attached, or it may be some surface which is made out of metal and expanded to provide a collector surface. The top surface serves to pick up heat from the sun and heat is transferred to the inside which contains a refrigerant charge, as an evaporator in a part of a heat pump system. The underside of the plate serves as an evaporator plate for an ice making heat pump when water is sprayed upon it from below.
The advantages of such a combination plate is that when the ambient temperatures are relatively warm and heat may be picked up from the sun, such as at temperatures of 32.degree. or above, the plate is used as a collector plate for a solar assisted heat pump. However, when the sun is obscured or during the night a drop in ambient temperature will result in a drop in suction pressure at the compressor and will cause a control to turn on a water spray at the proper time and spray water up on the under surface of the collector plate. With a proper arrangement water may also be sprayed on from above. Accordingly, due to the drop in suction pressure, freezing will now occur on the plate and ice will be formed. Thus efficiency may be maintained as in an ice making heat pump system. The collector plate can be harvested at intervals to free it from ice and the ice will simply fall free from the collector plate during the harvesting cycle. A slot can be provided at the lower end of the collector plate for ice to slide down a duct and into a storage bin in the basement or other room. Thus a very practical combination of collector and ice making evaporator is provided and controls for this system are extremely simple since the refrigerant continues to flow through the same collector plate whether the plate is being used as a solar collector or an ice making evaporator.